In woodwork of many different types, it is necessary to use strips to finish exposed edges. While the problem may exist with lumber of the best quality, it is particularly troublesome in making such products as valances, cabinets, cabinet doors and the like where curved edges, S-curves for example, are routinely required and where plywood and composition boards are commonly used.
Extruded plastic finishing strips are provided for attachment to the exposed edges of such structures. The strips are T-shaped in cross section with a tongue extending lengthwise and centrally of the face. Extruded strips of ethyl cellulose have proved satisfactory. In practice, each exposed edge of the woodwork is provided with a central slot, typically one-sixteenth of an inch in width and of a depth to receive the tongue with the under portions of the face engaging at least the margins of the edge. In practice, glue is used to securely anchor the tongues in the slots and the tongues of such strips are formed with ribs extending lengthwise of each of their sides providing barbs to facilitate effective anchorage.
Such strips provide a satisfactory basis for edge-finishing and are easily produced in a wide range of shapes and colors. They do, however, present certain problems arising from the fact that the tongues make it impossible to bend the faces for curves of either an inside or outside radius. If lengths of such strips are provided in coils of a relatively large size, the faces twist enough to cause noticeable irregularities which must be removed before the strip is used. As a consequence, the strips are often supplied in straight lengths, sixteen feet, for example, and packaged in tubes although such relatively short lengths lead to a relatively large amount of waste as compared to coils containing, say, fifty feet strips to enable a finishing strip to be applied to curved edges, it is necessary for its tongue to the cut at spaced intervals at right angles to the face to enable the face to be bent in the required direction. This is usually done in the shop by repeatedly advancing the tongue against a band saw. Aside from the risk of injury to the operator, there is the difficulty of making such cuts of adequate depth without cutting into the face.